Radiators for heating in homes, apartments, offices, and other multi-unit buildings suffer from a number of issues related to temperature control and energy efficiency. Particularly in large cities such as New York, steam and hot-water-heated apartment buildings are notorious for their heating issues, exemplified by open apartment windows during the winter heating season. These issues are often exacerbated by city regulations that require landlords to keep apartments at a temperature of at least 68 degrees Fahrenheit (F)/20 degrees Celsius (C), or higher. Additionally, the fact that steam and hot-water-heat heating systems provide heat to different spaces in a building with different efficiencies that are difficult to precisely control.
One approach to addressing the inconsistency in radiator heat is the use of thermostatic valves (TRVs) as an add-on to typical heating systems. TRVs can open and close a valve in response to temperature in a space. However, these devices cannot increase the heat exchange properties in a cold apartment, and need to be installed, balanced, and calibrated in each different installation location. Different equipment for different piping configurations may also be required. TRVs can also have reliability and maintenance issues, and a relatively short lifespan.
In addition to these heating issues is the energy usage in the boiler itself. Because of minimum temperature regulations boiler systems are usually run a certain percentage of the day and are keyed to keep the coldest apartment at the minimum temperature, and are conservatively run to ensure minimum temperatures. This is grossly wasteful, as the occupants of individual apartments that get overheated need to employ some strategy to keep their apartment at a comfortable temperature—the most popular method being venting the hot air outside and blatantly wasting energy.
Another approach to addressing heating inconsistencies is the use of fans to circulate air around radiators. Examples of such systems can be found in U.S. Pat. Nos. 2,489,187, 6,003,596, 6,808,018 and 7,841,389. These examples make use of fans and motors to circulate air around a radiator, effectively increasing the heat exchange properties of the radiator for an individual space. However, these devices do not deal with overheating.